The r11.5 and r12.1 databases are different so you will need to create a new instance for the r12.1 database. There are tools to unload many of the 11.5 tables and reload them in the new instance, but not the Favorites due to new options and changes that were in r12.1.
Most of the existing configurations can be migrated using the r12.1 Web Viewer 11.5 Database Export tool. The tool processes selected configuration settings from an r11.0 or r11.5 database. The tool exports the settings to 3 XML files that can then be uploaded into the Version r12.1 database using the Version r12.1 import feature. The database upgrade does not modify the existing r11.5 database, but only copies the r11.5 configuration.
This is what is contained in the 3 XML files:
Please refer to the Installation Guide, Section Upgrading from 11.0 or 11.5 to 12.1 for more information.